This invention relates to multi-layer metal structures having heat insulation characteristics, and is particularly directed to structural components of this class especially adapted for use in supersonic and hypersonic aircraft.
A major problem in the design of aircraft and aerospace structural components is the production of such components which will not only withstand the severe stress loads imposed by the speeds and altitudes of modern aircraft, particularly supersonic and hypersonic aircraft, but in addition to design structural components of this type which will also withstand the high thermal loads also imposed under these conditions.
Further, primary structural components of the above type heretofore produced have been of a relatively complex nature, requiring several stages for fabrication.
Illustrative of prior art metal structures are the following patents.
Kirk, et al U.S Pat. No. 3,029,910 discloses a composite structural unit for use as a metallic aircraft component in the form of a bead stiffened composite panel having an outer skin, an inner skin formed with beads to give the structure rigidity, a core material within the beads to further increase the structural rigidity and various strengthening edge members and doublers, all bonded together by a suitable bonding material. The structural component is assembled in several stages of assembly.
Shipley, et al U.S. Pat. No. 3,037,592 discloses a crisscross core for laminated metal structures which comprises a plurality of corrugated metal core elements assembled side-by-side in parallel alignment with the peaks of the corrugations of each element in contact with and secured to the valleys of the corrugations of adjoining core elements. Such metal structures are also fabricated in several stages.
The metal structures of the above-illustrated patents are basically employed as the primary structure, and no thermal insulation property is attributed to such structural components.
Thus, where insulation is required in conjunction with such structural members, a separate insulation member of non-structural characteristics is employed, in the nature of parasitic or passive insulation.
One object of the present invention is the production of a novel primary metal structure multi-layer insulation component.
Another object is to provide a multi-layer structural metal component having insulating characteristics particularly adapted for use in high speed aircraft, especially supersonic and hypersonic aircraft, and avoiding the need for a separate insulation member.
A still further object of the invention is the provision of a multi-layer metal structure produced by diffusion bonding and superplastic forming, wherein the intermediate layers of the structure are spaced from each other and form a reflective shield which carries the load and also acts as an insulator.
Yet another object of the invention is to provide efficient procedure for the fabrication of the aforementioned primary structure multi-layer metal insulation component of the invention.